Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
The wind turbine tower is typically constructed of multiple tower sections that are stacked and secured together. Further, it is common for wind turbine components such as the tower sections to be transported, e.g. on shipping vessels, to their desired destinations and/or stored. Certain cargo shipping vessels have weather decks that are equipped with accessible locking mechanisms such as conventionally known semi-automatic twist-lock mechanisms for releasably securing conventional cargo containers (e.g., rectangular, box-shapes cargo containers) thereto. The cargo containers have corresponding locking mechanisms at their bottom corners for mating with the locking mechanisms on the deck, and at their top corners to lock together stacked cargo containers. The ship's locking mechanisms are thus spaced across the width of the deck and located intermittently longitudinally of the deck.
For shipping purposes, wind turbine tower sections—which are typically cylindrical or frusto-conical—are fitted at both ends with a support member having a bottom that defines a pair of spaced apart feet or a straight, flat surface for stably resting the tower section on the ship's deck and for preventing the tower section from rolling. Additional locking mechanisms may be located at the top of the support member to permit stacking (in side-by-side relationship) of tower sections in the same manner as a cargo container.
Existing shipping or storage fixtures for wind tower sections, however, accommodate limited tower types and sizes. As such, introduction of new tower designs require lengthy engineering analysis, redesign of shipping fixtures, and/or large scale investment in new fixtures.
Additionally, some shipping vessels that are used to transport wind turbine tower sections have decks or floors with a maximum pressure rating. As larger wind turbine tower sections are being used and transported, the weight of the sections that are transported is increasing and the pressure they exert on various shipping floors is increasing. While it would be desirable to increase the number of tower sections that can be loaded within a single shipping vessel, it is also important to heed the load limits thereof.
Therefore, there is a need for a system and method for transporting and/or storing tower sections of wind turbines that enables stacking of the tower sections and accommodates a wide range of tower section bolt patterns, diameters, and/or loads.